1. Technical Field
2. Description of the Related Art
The present invention—involving sheet-folding apparatuses and sheet-folding-apparatus-equipped imaging systems that fold sheets sequentially delivered from an image-forming or like apparatus—relates to improvements in mechanisms that automatically fold sheets in half or in thirds, and that securely stow the sheets in a stacker.
Commonly known among this kind of sheet-folding apparatus are in general machines that fold in half or in thirds sheets delivered from an imaging or like apparatus, and deliver the folded sheets to and stow them in a stacker. Therein, for the folding style various techniques, such as Z-folding or gate-folding, are adopted depending on the application, such as mailing or filing. For example, Japanese Unexamined Pat. App. Pub. No. 2004-352419 discloses an apparatus in which provided within a conveyance path is a plurality of folding roller mechanisms that fold sheets by nipping them between the rollers in a process that takes over the conveyance of sheets from an imaging apparatus, and that stows the gate-, Z-, or otherwise-folded sheets in a stacker, or that binds the sheets together in a binding apparatus disposed downstream of the folding mechanisms.
In Japanese Unexamined Pat. App. Pub. No. 2004-189413 as well, a similar apparatus is proposed. Either of these machines folds sheets in half or thirds, in creases that are orthogonal to the direction of sheet conveyance. Also, Japanese Unexamined Pat. App. Pub. No. H06-016317 discloses an apparatus in which after sheets from an imaging apparatus are folded by folding rollers, a predetermined number of copies of the sheets drop into a stack on a tray, and after being stapled, the sheets are conveyed out in the orthogonal direction (creasing direction).
In folding with folding rollers sheets sequentially delivered from an imaging apparatus and loading/stowing them onto a downstream stacker, as described above conventionally adopted have been either a method whereby the folded sheets are conveyed in a direction orthogonal to the crease orientation and stowed, as with the above-cited Pat. App. Pub. Nos. 2004-352419 and 2004-189413, or a method whereby after having been bound together the folded sheets are conveyed in the orientation of the crease and stowed in the stacker, as with Pat. App. Pub. No. H06-016317. Consequently, delivering in an orientation orthogonal to the crease orientation in loading/stowing on the stacker, as disclosed in Pat. App. Pubs. Nos. 2004-352419 and 2004-189413, can cause a folded sheet to advance into the fold of a sheet that has already been stacked, giving rise to a sheet jam. FIG. 10 illustrates this, wherein in discharging a sheet from folding rollers into a stacking tray, the sheet S″ enters, as the arrow indicates, into the fold of already stacked sheet S′.
Therefore, conventionally a structure has been adopted that establishes the discharge outlet and stacking tray at different levels so that from the discharge outlet the sheet S″ falls on top of the uppermost sheet S′already stacked in the tray. This has meant that in the stacking tray sheets can get stowed in disarray, leading to the trouble of sheets scattering inside the apparatus, which compels the user to realign the sheets (bundles) stowed in the stacking tray after having taken them out of the tray. In the same way, with the structure in earlier cited Pat. App. Pub. No. H06-016317, folded sheets are dropped from the folding rollers directly into and stacked on a processing tray, and after sheets collated into a bundle on the processing tray are stapled, the sheet bundle is from an intermediary tray transported in the orientation of the crease and stowed in the stacking tray. Inasmuch as an intermediary tray is therefore disposed directly beneath the folding rollers, the apparatus layout is made complex; moreover, this intermediary tray carries with it the earlier described problem explained with FIG. 10.